Thrust bearing for seamless tube mills and the like



Aug. 30, 1949. J. w.- OFFUTT 2,480,381

THRUST BEARING FOR SEAMLESS TUBE MILLS AND THE LIKE Filed Dec. 20, 1945 3 Sheets-Sheet 1 \1 \1 0 Q 9% I Q I I I l I E 1 Q Q *TT Q l I g INVENTOR: Jaw W 5/77/77;

AWLA/QZZLW HIS ATTORNEY.

J. W. OFFUTT THRUST BEARING FOR SEAMLESS TUBE MILLS AND THE LIKE- Aug. 30, 1 949.

3 Sheets-Sheet 2 Filed Dec. 20, 1945 o \m N INVENTOR HIS ATTORNEY.

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3 Sheets-Sheet 3 Aug. 30, 1949. J. w. OFFUTT THRUST BEARING FOR SEAMLESS TUBE MILLS AND THE LIKE Filed Dec. 20, 1945 nlllill-lll HIS ATTORNEY.

Patented Aug. so, 1949 THRUST BEARING F MILLS AND John W. Oilutt, National Tube Jersey on SEAMLESS runs was 1.11m

Ellwood City, Pa., assigninto Company, a corporation of New Application December 20, 1945, Serial No. 636,125

Claims.

I This invention relates to seamless pipe or tube mills employing a rotatable and reciprocable mandrel bar and more particularly to the thrust bearings used therein.

In rolling seamless tional mills, a mandrel metal-working rolls by drel plug and bar are as it is helically advan lmandrel plug and bar.

pipe or tubing in convenpiug is held between the a mandrel bar. The manrotated by the workpiece ced by the rolls over the Since the workpiece is telescoped over the mandrel bar ,during the rolling operation, draw the mandrel bar it is necessary to retract or withfrom the metal-working position in order to remove the workpiece therefrom. The rearward end of bearing which permits free mandrel bar while holding it thrust or movement. In convensecured to a thrust rotation of the against endwise tlonal mills, the thrust block that is slidable onways the mill whereby the mandrel the outlet bed of the mandrel bar is bearing is mounted in a forming part of bar is retracted and repositioned by reciprocating the thrust bearing ways by means of an actuated cable running vantages which result and operating expense. are large enough and block in such slideair cylinder or a motorover a drum and idler.

Such an arrangement has a number of disadin excessive maintenance Thrust bearings which for large mandrels are too heavy for smaller mandrels whereby the inertia and friction effect prevent bearings require large mount- Moreover the large free rotation thereof.

ings resulting in large and heavy housings having a substantial inertia effect thereby requiring considerable power to bar carriage and housing at reciprocate the mandrel sufllcient speed to obtain fast operation of the mill. Due to the bearing and housing traveling with the carriage,

it is not practical to provide circulating lubrication. Splash lubrication calls for constant oil levels in the bearing compartment and due to the restricted volume of lubricant, no means of carrying awayheat or ispossible. This too frequent due over in conventional designs,

means to improper lubrication. Morefiltering of the lubricant that bearing failures are the point of attachment of the piercer bar to the thrust bearing spindle is outside of the bearing thereby placin the'spindle under cantilever stresses due to the unbalance of the rotating causes excessive radial to the bar. ings and housings,

bar. This condition load on the bearing next This in turn necessitates larger bearthereby increasing the inertia eilfect before mentioned. The result of this is that on mills processing a large range of workcome limitations on bearings sizes by thrust bearing spindle at the speed 'piece diameters, a thrust bearing that is large enough to stand up when making the larger sizes is so large that the resistance to turning is so great that the small bar used on the smaller sizes, will not turn freely, thereby causing the pier'cer point to turn on the bar cap, with excessive wear on both.

It is accordingly an object of this invention to overcome the foregoing disadvantages by providing a non-traveling thrust bearing and block for seamless tube mandrel bars.

It is a further object of this invention to overrotating the imparted to the mandrel plug during the metal-working operation.

It is another object of the present invention to provide a thrust bearing and housing which permits continuous lubrication of the bearing It is a still further object of the present invention to provide a thrust bearing and housing that is simple and rugged in design and durable in operation.

The foregoing and further objects'will be apparent from the specification and drawings, wherein:

Figure lis a plan view of a seamless tube mill showing the mandrel bar and thrust bearing;

Figure 2- is a side elevation of my improved thrust bearing arrangement;

Figure 3 is a section on line III-III of Figure 2;

' Figure 4 is an end view on line IV-IV of Figure Figure 5 is an end view on line V-V of Figure 2; and Figure 6 is. a longitudinal section. Referring more particularly to 'the drawings, the numeral 2 designates a pair of metal-working rolls between which a mandrel plug 6 is held in metal-working position by a mandrel bar 4. After a tubular workpiece A has been completely rolled between the metal-working rolls and over the intermediately disposed mandrel plug 6, and has been telescoped thereby over the mandrel bar 4, it is removed from the mill by withdrawing the mandrel bar and moving it to an adjacent skidway 8 by conventional kick-oil arms (not shown).

The mandrel bar I is securely connected to an enlarged head portion Ill, having a shoulder l2 of a tubular extension bar 14. The rearward end of the extension bar It is crosshead it, which is actuated by the piston l8 of a suitable air cylinder IQ for reciprocating the attached to a traveling bar I4 by a flexible hose 22 mandrel bar to remove a workpiece therefrom and reposition it in itsmetal-working position after the workpiece has been discharged from the outlet trough. Cooling fluid may be provided for the mandrel plug 6 through bar 4 and extension attached to the rear end of the extension connected to a source of fluid under suitable pressure.

A split housing 30 surrounds the bar 4 and extension bar l4 on both sides of the head In and is slidably mounted in a base plate 82 and can be adjusted longitudinally thereof by a screw 84. A rotatable spindle 36 is mounted within the housing 38 by means of forward radial bearing 88 and rearward radial bearing 40, and is held against axial thrust rearwardly of the housing by an intermediate thrust bearing 42. Suitable lubricant may be supplied to the bearings by inlet pipes 44 and withdrawn through pipes 46. The pipes 44 and 46 are connected to conventional lubricant filtering and circulating apparatus whereby a constant supply of lubricant is maintained in the bearings. The spindle 86 has a pulley 48 keyed thereto so that it may be driven at any speed desired by a variable speed motor 60 through V-belts 52. To insure that the mandrel bar is driven at the same speed as it is being rotated, a plus and minus reading ammeter may be included in the motor circuit to show whether the motor is being driven by the bar or the motor is driving the bar so that the motor can be adjusted to the correct speed.

An annular shoulder 60 surrounds the rotatable spindle 36 forwardly of the thrust bearing 42 and is provided with concave wear-receiving inserts 62. Four T-shaped fingers 64 having convex heads 66 are pivotally mounted in the spindle 86 midway of their length on pins 68, so that the heads 66 engage insert 62. A gear segment is provided on the outer side of the fingers 64 on arcs with the pins 68 as their centers. A slidable sleeve 12 surrounds the spindle 86 around the fingers 64 and has an annular rack 14 therein which engages the gear segments 10. The rack I4 is normally spring-biased by springs 16 to a forward position but permits a limited movement of the rack relative to the sleeve. Thus rearward movement of the sleeve pivotally moves the fingers 64 so that the inner end or lug 18 is disposed in the path of the mandrel bar 4 so as to engage the shoulder l2 thereof. Also the sleeve slides over the outer lugs 80 to lock the fingers in this position. The fit of the fingers 64 on pins 68 is loose enough that none of the axial thrust set up on the bar during rolling is absorbed by the pins 68 but rather by the comparatively large surfaces of the wearing insert 62. The upper lugs 86 of the fingers are flush with the outer surfaces of shoulder 68 and insert 62 so that the sleeve can slide thereover to lock the fingers in position for holding the mandrel bar against axial thrust.

An air cylinder 82 is mounted adjacent the ring 12, the piston 84 of which is connected to the ring 12 by link 86, arms 88 and yoke 90 mounted therearound.

Due to the rack 14 being slidably mounted in the ring 12 when air is admitted to the cylinder 82 to release the bar, move axially far enough to uncover the upper lugs 80 of the fingers 64 by compressing the springs 16. After the ring enough to-uncover the lugs 88, the fingers 64 will pivot about pins 68 until the lower lugs 18 have moved outwardly to clear the head Ill. The bar can then be retracted by operation of cylinthe yoke 80 and ring 12 will 12 has moved far der and piston l8. Forward movement of the bar is controlled on the return stroke of piston I. by spring-mounted stops 82.

Accurate adjustment of the plug 6 relative to the rolls 2 is obtained by the screw 84. A stationary guide or bearing 84 may be provided in front of the rotary spindle to act as a guide when the bar is reciprocated.

Since it is undesirable at times to have the bar and plug rotating when there is no workpiece between the rolls, the fingers 64 are so arranged that they do not clamp the head l0 but the only contact therebetween is between the shoulder l2 and lugs 18. Thus until these surfaces are brought into frictional engagement by axial thrust on the bar due to a workpieceentering the gorge of the rolls, the rotation of the spindle will not be imparted to the bar. However, when a workpiece enters the gorge and is against the mandrel plug, the frictional engagement between the shoulder l2 and lugs 16 will form a driving connection between the spindle and the bar whereby the latter will be driven by the variable speed motor 50.

Since the cooling water is supplied to and discharged from the bar at the rear end of the extension bar l4 problem of the water getting into the thrust bearing and displacing the lubricant as in conventional bearings.

While I have shown and described one specific embodiment of my invention, it will be understood that this embodiment is merely for the purpose of-illustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim:

1. A thrust bearing for seamless tube mill mandrel bars comprising a longitudinally slidable housing, means for longitudinally adjusting said housing, a rotatable tubular spindle in said housing with a mandrel bar extending therethrough, a shoulder on said mandrel bar disposed interiorly of said spindle, a thrust bearing between said spindle and said housing, retractible fingers in said spindle adapted to engage said shoulder to transmit axial thrust thereon to said spindle, and means for retracting said fingers to permit said mandrel bar to be withdrawn through said spindle, said means comprising a gear segment on said fingers, a collar mounted around said fingers, an annular rack in said collar engaging said gear segments and means for reciprocating said collar.

2. A thrust bearing for seamless tube mill mandrel bars comprising a longitudinally slidable housing, means for longitudinally adjusting said housing, a rotatable tubular spindle in said housing with a mandrel bar extending therethrough, a shoulder on said mandrel bar disposed interiorly of said spindle, a thrust bearing between said spindle and said housing, a plurality of T-shaped retractible fingers pivotally mounted in said spindle, the inner lug of the head of the T-shaped members being adapted to be moved inwardly to engage the shoulder on said bar to transmit axial thrust thereon to said spindle, a gear segment on the outer side of the leg portion of said T-shaped members, a collar disposed around said fingers, an annular rack in said collar engaging the gear segments on said fingers, and means for reciprocating said collar, to pivot said fingers to move said inner lug inwardly so as to be engaged by said shoulder or outwardly to permit pushed at the crosshead l6, there is no the mandrel bar to be retracted through said housing and spindle.

3. A thrust bearing for seamless tube mill mandrel bars comprising a longitudinally slidable housing, means for longitudinally adjusting said housing, a rotatable tubular spindle in said housing with a mandrel bar extending therethrough, a shoulder on said mandrel bar disposed interiorly of said spindle, a thrust bearing between said spindle and said housing, a plurality of T-shaped retractible fingers pivotally mounted in said spindle with a lost motion mounting and with the lugs of the head portion disposed radially of the longitudinal axis of the mandrel bar, the inner lug of the head being adapted to be engaged by said shoulder when said lug is moved inwardly, the head of said T-shaped member having a convex face, a concave insert member in said spindle adjacent said convex head adapted to be engaged thereby when said inner lugs are engaged by said shoulder to transmit thrust from said mandrel bar to said thrust bearing.

4. A thrust bearing for seamless tube mill mandrel bars comprising a longitudinally slidable housing, means for longitudinally adjusting said housing, a rotatable tubular spindle in said housing with a mandrel bar extending therethrough, a shoulder on said mandrel bar disposed interiorly of said spindle, a thrust bearing between said spindle and said housing, a plurality of T-shaped retractible fingers pivotally mounted in said spindie with a lost motion mounting and with the lugs of the head portion disposed radially of the longitudinal axis of the mandrel bar, the inner lug of the head being adapted to be engaged by said shoulder when said lug is moved inwardly, said T-shaped member having a convex face on the head thereof, a concave annular insert member in said spindle adjacent said convex head adapted to be engaged thereby when said inner lugs are engaged by said shoulder to transmit thrust from said mandrel bar to said thrust bearing, a gear segment on the outer side of the leg portion of T-shaped members, a collar around said T-shaped members, an annular rack in said collar engaging the gear segments on said fingers and means for reciprocating said collar to pivot said fingers to move said inner lug inwardly so as to be engaged by said shoulder or outwardly to permit the mandrel bar to be retracted through said housing and spindle.

5. A thrust bearing for seamless tube mill mandrel bars comprising a longitudinally slidable housing, means for longitudinally adjusting said housing, a rotatable tubular spindle in said housing with a mandrel bar extending therethrough, a shoulder on said mandrel bar disposed interiorly of said spindle, a thrust bearing between said spindle and said housing, a plurality of T-shaped retractible fingers pivotally mounted in said spindle with the lugs of the head portion being disposed radially of the longitudinal axis of the mandrel bar, a gear segment on the outer side of the leg portion of said T-shaped fingers, a collar disposed around said fingers, an annular rack in said collar engaging the gear segments on said fingers, said rack being slidably mounted in said collar and being spring-biased away from the head of the T-shaped members, said collar being adapted to slide over the outer lug of said T- shaped head to lock the head in its inner position, said spring-biased mounting of the rack in said collar permitting said collar to slide 011 said upper lug before the engagement of the racks and gear segments begins the pivotal movement of said fingers.

JOHN W. OFFUTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,088,650 Brinkman Feb. 24, 1914 1,240,513 Thust Sept. 18, 1917 2,024,514 Diescher Dec. 17,1935 2,263,744 Smith Nov. 25,1941 

